Here's my first attempt at this one. I'm not real happy with the tablecloth, due to the mapping at the edge, and definitely not with the straw, so still plenty of work to do :-)
The background is a bitmap - is that allowed?

I like the glass idea. If you could get rid of the white part... or maybe that's the liquid. Striped glass is nice though. The background is allowed. but if the picture on the postcard isn't yours agil might frown.

Nice glass, maybe increase the scale of the material on the tablecloth and give a it a cloth bump?

Many thanks for the comments. The tablecloth is a procedural texture but I've solved the edge problem by using a bitmap instead. I'll try a cloth bump, but I originally thought this could be one of those plastic tablecloths you sometimes see in cheap cafes :-) Needs some specularity if so. I also need to think about the liquid, it's too bright as it is. Both bitmaps are mine - taken in Gibraltar, the backdrop is of the botanical gardens, the postcard is the cable car taken from the top of the Rock.

Okay, here's the second attempt. I've changed a few things since the previous one. I'm quite pleased with the glass, especially as this is a procedural, not a bitmap. Still some work to do with the straw and the lighting though, and I'd like to get frost or condensation drops on the glass.

The glass and the cloth, liquid is all really good. Like the colored shadow to.. caustic I think they call that. Looks super good.